RT-Thread - IPC Sync

/**
 * This function will lock the thread scheduler.
 */
void rt_enter_critical(void)
{
    register rt_base_t level;

    /* disable interrupt */
    level = rt_hw_interrupt_disable();

    /*
     * the maximal number of nest is RT_UINT16_MAX, which is big
     * enough and does not check here
     */
    rt_scheduler_lock_nest ++;

    /* enable interrupt */
    rt_hw_interrupt_enable(level);
}
RTM_EXPORT(rt_enter_critical);

/**
 * This function will unlock the thread scheduler.
 */
void rt_exit_critical(void)
{
    register rt_base_t level;

    /* disable interrupt */
    level = rt_hw_interrupt_disable();

    rt_scheduler_lock_nest --;

    if (rt_scheduler_lock_nest <= 0)
    {
        rt_scheduler_lock_nest = 0;
        /* enable interrupt */
        rt_hw_interrupt_enable(level);

        rt_schedule();
    }
    else
    {
        /* enable interrupt */
        rt_hw_interrupt_enable(level);
    }
}

/**
 * Get the scheduler lock level
 *
 * @return the level of the scheduler lock. 0 means unlocked.
 */
rt_uint16_t rt_critical_level(void)
{
    return rt_scheduler_lock_nest;
}
RTM_EXPORT(rt_critical_level);

#ifdef RT_USING_SEMAPHORE
/**
 * Semaphore structure
 */
struct rt_semaphore
{
    struct rt_ipc_object parent;                        /**< inherit from ipc_object */

    rt_uint16_t          value;                         /**< value of semaphore. */
};
typedef struct rt_semaphore *rt_sem_t;
#endif

/**
 * IPC flags and control command definitions
 */
#define RT_IPC_FLAG_FIFO                0x00            /**< FIFOed IPC. @ref IPC. */
#define RT_IPC_FLAG_PRIO                0x01            /**< PRIOed IPC. @ref IPC. */

#define RT_IPC_CMD_UNKNOWN              0x00            /**< unknown IPC command */
#define RT_IPC_CMD_RESET                0x01            /**< reset IPC object */

#define RT_WAITING_FOREVER              -1              /**< Block forever until get resource. */
#define RT_WAITING_NO                   0               /**< Non-block. */

/**
 * This function will create a semaphore from system resource
 *
 * @param name the name of semaphore
 * @param value the init value of semaphore
 * @param flag the flag of semaphore
 *
 * @return the created semaphore, RT_NULL on error happen
 *
 * @see rt_sem_init
 */
rt_sem_t rt_sem_create(const char *name, rt_uint32_t value, rt_uint8_t flag)
{
    rt_sem_t sem;

    RT_DEBUG_NOT_IN_INTERRUPT;

    /* allocate object */
    sem = (rt_sem_t)rt_object_allocate(RT_Object_Class_Semaphore, name);
    if (sem == RT_NULL)
        return sem;

    /* init ipc object */
    rt_ipc_object_init(&(sem->parent));

    /* set init value */
    sem->value = value;

    /* set parent */
    sem->parent.parent.flag = flag;

    return sem;
}
RTM_EXPORT(rt_sem_create);

/**
 * This function will initialize a semaphore and put it under control of
 * resource management.
 *
 * @param sem the semaphore object
 * @param name the name of semaphore
 * @param value the init value of semaphore
 * @param flag the flag of semaphore
 *
 * @return the operation status, RT_EOK on successful
 */
rt_err_t rt_sem_init(rt_sem_t    sem,
                     const char *name,
                     rt_uint32_t value,
                     rt_uint8_t  flag)
{
    RT_ASSERT(sem != RT_NULL);

    /* init object */
    rt_object_init(&(sem->parent.parent), RT_Object_Class_Semaphore, name);

    /* init ipc object */
    rt_ipc_object_init(&(sem->parent));

    /* set init value */
    sem->value = value;

    /* set parent */
    sem->parent.parent.flag = flag;

    return RT_EOK;
}
RTM_EXPORT(rt_sem_init);

/**
 * This function will delete a semaphore object and release the memory
 *
 * @param sem the semaphore object
 *
 * @return the error code
 *
 * @see rt_sem_detach
 */
rt_err_t rt_sem_delete(rt_sem_t sem)
{
    RT_DEBUG_NOT_IN_INTERRUPT;

    /* parameter check */
    RT_ASSERT(sem != RT_NULL);
    RT_ASSERT(rt_object_get_type(&sem->parent.parent) == RT_Object_Class_Semaphore);
    RT_ASSERT(rt_object_is_systemobject(&sem->parent.parent) == RT_FALSE);

    /* wakeup all suspend threads */
    rt_ipc_list_resume_all(&(sem->parent.suspend_thread));

    /* delete semaphore object */
    rt_object_delete(&(sem->parent.parent));

    return RT_EOK;
}
RTM_EXPORT(rt_sem_delete);

/**
 * This function will detach a semaphore from resource management
 *
 * @param sem the semaphore object
 *
 * @return the operation status, RT_EOK on successful
 *
 * @see rt_sem_delete
 */
rt_err_t rt_sem_detach(rt_sem_t sem)
{
    /* parameter check */
    RT_ASSERT(sem != RT_NULL);
    RT_ASSERT(rt_object_get_type(&sem->parent.parent) == RT_Object_Class_Semaphore);
    RT_ASSERT(rt_object_is_systemobject(&sem->parent.parent));

    /* wakeup all suspend threads */
    rt_ipc_list_resume_all(&(sem->parent.suspend_thread));

    /* detach semaphore object */
    rt_object_detach(&(sem->parent.parent));

    return RT_EOK;
}
RTM_EXPORT(rt_sem_detach);

/**
 * This function will take a semaphore, if the semaphore is unavailable, the
 * thread shall wait for a specified time.
 *
 * @param sem the semaphore object
 * @param time the waiting time
 *
 * @return the error code
 */
rt_err_t rt_sem_take(rt_sem_t sem, rt_int32_t time)
{
    register rt_base_t temp;
    struct rt_thread *thread;

    /* parameter check */
    RT_ASSERT(sem != RT_NULL);
    RT_ASSERT(rt_object_get_type(&sem->parent.parent) == RT_Object_Class_Semaphore);

    RT_OBJECT_HOOK_CALL(rt_object_trytake_hook, (&(sem->parent.parent)));

    /* disable interrupt */
    temp = rt_hw_interrupt_disable();

RT_DEBUG_LOG(RT_DEBUG_IPC, ("thread %s take sem:%s, which value is: %d\n",
                            rt_thread_self()->name,
                            ((struct rt_object *)sem)->name,
                            sem->value));

if (sem->value > 0)
{
    /* semaphore is available */
    sem->value --;

    /* enable interrupt */
    rt_hw_interrupt_enable(temp);
}

else
{
    /* no waiting, return with timeout */
    if (time == 0)
    {
        rt_hw_interrupt_enable(temp);

        return -RT_ETIMEOUT;
    }

else
{
    /* current context checking */
    RT_DEBUG_IN_THREAD_CONTEXT;

    /* semaphore is unavailable, push to suspend list */
    /* get current thread */
    thread = rt_thread_self();

    /* reset thread error number */
    thread->error = RT_EOK;

    RT_DEBUG_LOG(RT_DEBUG_IPC, ("sem take: suspend thread - %s\n",
                                thread->name));

    /* suspend thread */
    rt_ipc_list_suspend(&(sem->parent.suspend_thread),
                        thread,
                        sem->parent.parent.flag);

/* has waiting time, start thread timer */
if (time > 0)
{
    RT_DEBUG_LOG(RT_DEBUG_IPC, ("set thread:%s to timer list\n",
                                thread->name));

    /* reset the timeout of thread timer and start it */
    rt_timer_control(&(thread->thread_timer),
                     RT_TIMER_CTRL_SET_TIME,
                     &time);
    rt_timer_start(&(thread->thread_timer));
}

            /* enable interrupt */
            rt_hw_interrupt_enable(temp);

            /* do schedule */
            rt_schedule();

            if (thread->error != RT_EOK)
            {
                return thread->error;
            }
        }
    }

    RT_OBJECT_HOOK_CALL(rt_object_take_hook, (&(sem->parent.parent)));

    return RT_EOK;
}
RTM_EXPORT(rt_sem_take);

/**
 * This function will try to take a semaphore and immediately return
 *
 * @param sem the semaphore object
 *
 * @return the error code
 */
rt_err_t rt_sem_trytake(rt_sem_t sem)
{
    return rt_sem_take(sem, 0);
}
RTM_EXPORT(rt_sem_trytake);

/**
 * This function will release a semaphore, if there are threads suspended on
 * semaphore, it will be waked up.
 *
 * @param sem the semaphore object
 *
 * @return the error code
 */
rt_err_t rt_sem_release(rt_sem_t sem)
{
    register rt_base_t temp;
    register rt_bool_t need_schedule;

    /* parameter check */
    RT_ASSERT(sem != RT_NULL);
    RT_ASSERT(rt_object_get_type(&sem->parent.parent) == RT_Object_Class_Semaphore);

    RT_OBJECT_HOOK_CALL(rt_object_put_hook, (&(sem->parent.parent)));

    need_schedule = RT_FALSE;

    /* disable interrupt */
    temp = rt_hw_interrupt_disable();

RT_DEBUG_LOG(RT_DEBUG_IPC, ("thread %s releases sem:%s, which value is: %d\n",
                            rt_thread_self()->name,
                            ((struct rt_object *)sem)->name,
                            sem->value));

if (!rt_list_isempty(&sem->parent.suspend_thread))
{
    /* resume the suspended thread */
    rt_ipc_list_resume(&(sem->parent.suspend_thread));
    need_schedule = RT_TRUE;
}

else
    sem->value ++; /* increase value */

    /* enable interrupt */
    rt_hw_interrupt_enable(temp);

    /* resume a thread, re-schedule */
    if (need_schedule == RT_TRUE)
        rt_schedule();

    return RT_EOK;
}
RTM_EXPORT(rt_sem_release);

#ifdef RT_USING_MUTEX
/**
 * Mutual exclusion (mutex) structure
 */
struct rt_mutex
{
    struct rt_ipc_object parent;                        /**< inherit from ipc_object */

    rt_uint16_t          value;                         /**< value of mutex */

    rt_uint8_t           original_priority;             /**< priority of last thread hold the mutex */
    rt_uint8_t           hold;                          /**< numbers of thread hold the mutex */

    struct rt_thread    *owner;                         /**< current owner of mutex */
};
typedef struct rt_mutex *rt_mutex_t;
#endif

/**
 * This function will create a mutex from system resource
 *
 * @param name the name of mutex
 * @param flag the flag of mutex
 *
 * @return the created mutex, RT_NULL on error happen
 *
 * @see rt_mutex_init
 */
rt_mutex_t rt_mutex_create(const char *name, rt_uint8_t flag)
{
    struct rt_mutex *mutex;

    RT_DEBUG_NOT_IN_INTERRUPT;

    /* allocate object */
    mutex = (rt_mutex_t)rt_object_allocate(RT_Object_Class_Mutex, name);
    if (mutex == RT_NULL)
        return mutex;

/* init ipc object */
rt_ipc_object_init(&(mutex->parent));

mutex->value              = 1;
mutex->owner              = RT_NULL;
mutex->original_priority  = 0xFF;
mutex->hold               = 0;

    /* set flag */
    mutex->parent.parent.flag = flag;

    return mutex;
}
RTM_EXPORT(rt_mutex_create);

/**
 * This function will initialize a mutex and put it under control of resource
 * management.
 *
 * @param mutex the mutex object
 * @param name the name of mutex
 * @param flag the flag of mutex
 *
 * @return the operation status, RT_EOK on successful
 */
rt_err_t rt_mutex_init(rt_mutex_t mutex, const char *name, rt_uint8_t flag)
{
    /* parameter check */
    RT_ASSERT(mutex != RT_NULL);

    /* init object */
    rt_object_init(&(mutex->parent.parent), RT_Object_Class_Mutex, name);

    /* init ipc object */
    rt_ipc_object_init(&(mutex->parent));

    mutex->value = 1;
    mutex->owner = RT_NULL;
    mutex->original_priority = 0xFF;
    mutex->hold  = 0;

    /* set flag */
    mutex->parent.parent.flag = flag;

    return RT_EOK;
}
RTM_EXPORT(rt_mutex_init);

/**
 * This function will delete a mutex object and release the memory
 *
 * @param mutex the mutex object
 *
 * @return the error code
 *
 * @see rt_mutex_detach
 */
rt_err_t rt_mutex_delete(rt_mutex_t mutex)
{
    RT_DEBUG_NOT_IN_INTERRUPT;

    /* parameter check */
    RT_ASSERT(mutex != RT_NULL);
    RT_ASSERT(rt_object_get_type(&mutex->parent.parent) == RT_Object_Class_Mutex);
    RT_ASSERT(rt_object_is_systemobject(&mutex->parent.parent) == RT_FALSE);

    /* wakeup all suspend threads */
    rt_ipc_list_resume_all(&(mutex->parent.suspend_thread));

    /* delete semaphore object */
    rt_object_delete(&(mutex->parent.parent));

    return RT_EOK;
}
RTM_EXPORT(rt_mutex_delete);

/**
 * This function will detach a mutex from resource management
 *
 * @param mutex the mutex object
 *
 * @return the operation status, RT_EOK on successful
 *
 * @see rt_mutex_delete
 */
rt_err_t rt_mutex_detach(rt_mutex_t mutex)
{
    /* parameter check */
    RT_ASSERT(mutex != RT_NULL);
    RT_ASSERT(rt_object_get_type(&mutex->parent.parent) == RT_Object_Class_Mutex);
    RT_ASSERT(rt_object_is_systemobject(&mutex->parent.parent));

    /* wakeup all suspend threads */
    rt_ipc_list_resume_all(&(mutex->parent.suspend_thread));

    /* detach semaphore object */
    rt_object_detach(&(mutex->parent.parent));

    return RT_EOK;
}
RTM_EXPORT(rt_mutex_detach);

/**
 * This function will take a mutex, if the mutex is unavailable, the
 * thread shall wait for a specified time.
 *
 * @param mutex the mutex object
 * @param time the waiting time
 *
 * @return the error code
 */
rt_err_t rt_mutex_take(rt_mutex_t mutex, rt_int32_t time)
{
    register rt_base_t temp;
    struct rt_thread *thread;

    /* this function must not be used in interrupt even if time = 0 */
    RT_DEBUG_IN_THREAD_CONTEXT;

    /* parameter check */
    RT_ASSERT(mutex != RT_NULL);
    RT_ASSERT(rt_object_get_type(&mutex->parent.parent) == RT_Object_Class_Mutex);

    /* get current thread */
    thread = rt_thread_self();

    /* disable interrupt */
    temp = rt_hw_interrupt_disable();

RT_OBJECT_HOOK_CALL(rt_object_trytake_hook, (&(mutex->parent.parent)));

RT_DEBUG_LOG(RT_DEBUG_IPC,
             ("mutex_take: current thread %s, mutex value: %d, hold: %d\n",
              thread->name, mutex->value, mutex->hold));

/* reset thread error */
thread->error = RT_EOK;

if (mutex->owner == thread)
{
    /* it's the same thread */
    mutex->hold ++;
}

    else
    {
__again:
        /* The value of mutex is 1 in initial status. Therefore, if the
         * value is great than 0, it indicates the mutex is avaible.
         */
        if (mutex->value > 0)
        {
            /* mutex is available */
            mutex->value --;

            /* set mutex owner and original priority */
            mutex->owner             = thread;
            mutex->original_priority = thread->current_priority;
            mutex->hold ++;
        }

else
{
    /* no waiting, return with timeout */
    if (time == 0)
    {
        /* set error as timeout */
        thread->error = -RT_ETIMEOUT;

        /* enable interrupt */
        rt_hw_interrupt_enable(temp);

        return -RT_ETIMEOUT;
    }

else
{
    /* mutex is unavailable, push to suspend list */
    RT_DEBUG_LOG(RT_DEBUG_IPC, ("mutex_take: suspend thread: %s\n",
                                thread->name));

    /* change the owner thread priority of mutex */
    if (thread->current_priority < mutex->owner->current_priority)
    {
        /* change the owner thread priority */
        rt_thread_control(mutex->owner,
                          RT_THREAD_CTRL_CHANGE_PRIORITY,
                          &thread->current_priority);
    }

/* suspend current thread */
rt_ipc_list_suspend(&(mutex->parent.suspend_thread),
                    thread,
                    mutex->parent.parent.flag);

/* has waiting time, start thread timer */
if (time > 0)
{
    RT_DEBUG_LOG(RT_DEBUG_IPC,
                 ("mutex_take: start the timer of thread:%s\n",
                  thread->name));

    /* reset the timeout of thread timer and start it */
    rt_timer_control(&(thread->thread_timer),
                     RT_TIMER_CTRL_SET_TIME,
                     &time);
    rt_timer_start(&(thread->thread_timer));
}

/* enable interrupt */
rt_hw_interrupt_enable(temp);

/* do schedule */
rt_schedule();

if (thread->error != RT_EOK)
{
	/* interrupt by signal, try it again */
	if (thread->error == -RT_EINTR) goto __again;

    /* return error */
    return thread->error;
}

                else
                {
                    /* the mutex is taken successfully. */
                    /* disable interrupt */
                    temp = rt_hw_interrupt_disable();
                }
            }
        }
    }
    /* enable interrupt */
    rt_hw_interrupt_enable(temp);

    RT_OBJECT_HOOK_CALL(rt_object_take_hook, (&(mutex->parent.parent)));

    return RT_EOK;
}
RTM_EXPORT(rt_mutex_take);

/**
 * This function will release a mutex, if there are threads suspended on mutex,
 * it will be waked up.
 *
 * @param mutex the mutex object
 *
 * @return the error code
 */
rt_err_t rt_mutex_release(rt_mutex_t mutex)
{
    register rt_base_t temp;
    struct rt_thread *thread;
    rt_bool_t need_schedule;

    /* parameter check */
    RT_ASSERT(mutex != RT_NULL);
    RT_ASSERT(rt_object_get_type(&mutex->parent.parent) == RT_Object_Class_Mutex);

    need_schedule = RT_FALSE;

    /* only thread could release mutex because we need test the ownership */
    RT_DEBUG_IN_THREAD_CONTEXT;

    /* get current thread */
    thread = rt_thread_self();

    /* disable interrupt */
    temp = rt_hw_interrupt_disable();

RT_DEBUG_LOG(RT_DEBUG_IPC,
             ("mutex_release:current thread %s, mutex value: %d, hold: %d\n",
              thread->name, mutex->value, mutex->hold));

RT_OBJECT_HOOK_CALL(rt_object_put_hook, (&(mutex->parent.parent)));

/* mutex only can be released by owner */
if (thread != mutex->owner)
{
    thread->error = -RT_ERROR;

    /* enable interrupt */
    rt_hw_interrupt_enable(temp);

    return -RT_ERROR;
}

/* decrease hold */
mutex->hold --;

/* if no hold */
if (mutex->hold == 才會
{
    /* change the owner thread to original priority */
    if (mutex->original_priority != mutex->owner->current_priority)
    {
        rt_thread_control(mutex->owner,
                          RT_THREAD_CTRL_CHANGE_PRIORITY,
                          &(mutex->original_priority));
    }

/* wakeup suspended thread */
if (!rt_list_isempty(&mutex->parent.suspend_thread))
{
    /* get suspended thread */
    thread = rt_list_entry(mutex->parent.suspend_thread.next,
                           struct rt_thread,
                           tlist);

    RT_DEBUG_LOG(RT_DEBUG_IPC, ("mutex_release: resume thread: %s\n",
                                thread->name));

    /* set new owner and priority */
    mutex->owner             = thread;
    mutex->original_priority = thread->current_priority;
    mutex->hold ++;

    /* resume thread */
    rt_ipc_list_resume(&(mutex->parent.suspend_thread));

    need_schedule = RT_TRUE;
}

    else
    {
        /* increase value */
        mutex->value ++;

        /* clear owner */
        mutex->owner             = RT_NULL;
        mutex->original_priority = 0xff;
    }
}

    /* enable interrupt */
    rt_hw_interrupt_enable(temp);

    /* perform a schedule */
    if (need_schedule == RT_TRUE)
        rt_schedule();

    return RT_EOK;
}
RTM_EXPORT(rt_mutex_release);

#if defined(RT_USING_EVENT)
    /* thread event */
    rt_uint32_t event_set;
    rt_uint8_t  event_info;
#endif

#ifdef RT_USING_EVENT
/**
 * flag defintions in event
 */
#define RT_EVENT_FLAG_AND               0x01            /**< logic and */
#define RT_EVENT_FLAG_OR                0x02            /**< logic or */
#define RT_EVENT_FLAG_CLEAR             0x04            /**< clear flag */

/*
 * event structure
 */
struct rt_event
{
    struct rt_ipc_object parent;                        /**< inherit from ipc_object */

    rt_uint32_t          set;                           /**< event set */
};
typedef struct rt_event *rt_event_t;
#endif

/**
 * This function will create an event object from system resource
 *
 * @param name the name of event
 * @param flag the flag of event
 *
 * @return the created event, RT_NULL on error happen
 */
rt_event_t rt_event_create(const char *name, rt_uint8_t flag)
{
    rt_event_t event;

    RT_DEBUG_NOT_IN_INTERRUPT;

    /* allocate object */
    event = (rt_event_t)rt_object_allocate(RT_Object_Class_Event, name);
    if (event == RT_NULL)
        return event;

    /* set parent */
    event->parent.parent.flag = flag;

    /* init ipc object */
    rt_ipc_object_init(&(event->parent));

    /* init event */
    event->set = 0;

    return event;
}
RTM_EXPORT(rt_event_create);

/**
 * This function will initialize an event and put it under control of resource
 * management.
 *
 * @param event the event object
 * @param name the name of event
 * @param flag the flag of event
 *
 * @return the operation status, RT_EOK on successful
 */
rt_err_t rt_event_init(rt_event_t event, const char *name, rt_uint8_t flag)
{
    /* parameter check */
    RT_ASSERT(event != RT_NULL);

    /* init object */
    rt_object_init(&(event->parent.parent), RT_Object_Class_Event, name);

    /* set parent flag */
    event->parent.parent.flag = flag;

    /* init ipc object */
    rt_ipc_object_init(&(event->parent));

    /* init event */
    event->set = 0;

    return RT_EOK;
}
RTM_EXPORT(rt_event_init);

/**
 * This function will delete an event object and release the memory
 *
 * @param event the event object
 *
 * @return the error code
 */
rt_err_t rt_event_delete(rt_event_t event)
{
    /* parameter check */
    RT_ASSERT(event != RT_NULL);
    RT_ASSERT(rt_object_get_type(&event->parent.parent) == RT_Object_Class_Event);
    RT_ASSERT(rt_object_is_systemobject(&event->parent.parent) == RT_FALSE);

    RT_DEBUG_NOT_IN_INTERRUPT;

    /* resume all suspended thread */
    rt_ipc_list_resume_all(&(event->parent.suspend_thread));

    /* delete event object */
    rt_object_delete(&(event->parent.parent));

    return RT_EOK;
}
RTM_EXPORT(rt_event_delete);

/**
 * This function will detach an event object from resource management
 *
 * @param event the event object
 *
 * @return the operation status, RT_EOK on successful
 */
rt_err_t rt_event_detach(rt_event_t event)
{
    /* parameter check */
    RT_ASSERT(event != RT_NULL);
    RT_ASSERT(rt_object_get_type(&event->parent.parent) == RT_Object_Class_Event);
    RT_ASSERT(rt_object_is_systemobject(&event->parent.parent));

    /* resume all suspended thread */
    rt_ipc_list_resume_all(&(event->parent.suspend_thread));

    /* detach event object */
    rt_object_detach(&(event->parent.parent));

    return RT_EOK;
}
RTM_EXPORT(rt_event_detach);

/**
 * This function will send an event to the event object, if there are threads
 * suspended on event object, it will be waked up.
 *
 * @param event the event object
 * @param set the event set
 *
 * @return the error code
 */
rt_err_t rt_event_send(rt_event_t event, rt_uint32_t set)
{
    struct rt_list_node *n;
    struct rt_thread *thread;
    register rt_ubase_t level;
    register rt_base_t status;
    rt_bool_t need_schedule;

    /* parameter check */
    RT_ASSERT(event != RT_NULL);
    RT_ASSERT(rt_object_get_type(&event->parent.parent) == RT_Object_Class_Event);

    if (set == 0)
        return -RT_ERROR;

    need_schedule = RT_FALSE;

    /* disable interrupt */
    level = rt_hw_interrupt_disable();

/* set event */
event->set |= set;

RT_OBJECT_HOOK_CALL(rt_object_put_hook, (&(event->parent.parent)));

if (!rt_list_isempty(&event->parent.suspend_thread))
{
    /* search thread list to resume thread */
    n = event->parent.suspend_thread.next;
    while (n != &(event->parent.suspend_thread))
    {
        /* get thread */
        thread = rt_list_entry(n, struct rt_thread, tlist);

        status = -RT_ERROR;
        if (thread->event_info & RT_EVENT_FLAG_AND)
        {
            if ((thread->event_set & event->set) == thread->event_set)
            {
                /* received an AND event */
                status = RT_EOK;
            }
        }

else if (thread->event_info & RT_EVENT_FLAG_OR)
{
    if (thread->event_set & event->set)
    {
        /* save recieved event set */
        thread->event_set = thread->event_set & event->set;

        /* received an OR event */
        status = RT_EOK;
    }
}

/* move node to the next */
n = n->next;

/* condition is satisfied, resume thread */
if (status == RT_EOK)
{
    /* clear event */
    if (thread->event_info & RT_EVENT_FLAG_CLEAR)
        event->set &= ~thread->event_set;

            /* resume thread, and thread list breaks out */
            rt_thread_resume(thread);

            /* need do a scheduling */
            need_schedule = RT_TRUE;
        }
    }
}

    /* enable interrupt */
    rt_hw_interrupt_enable(level);

    /* do a schedule */
    if (need_schedule == RT_TRUE)
        rt_schedule();

    return RT_EOK;
}
RTM_EXPORT(rt_event_send);

/**
 * This function will receive an event from event object, if the event is
 * unavailable, the thread shall wait for a specified time.
 *
 * @param event the fast event object
 * @param set the interested event set
 * @param option the receive option, either RT_EVENT_FLAG_AND or
 *        RT_EVENT_FLAG_OR should be set.
 * @param timeout the waiting time
 * @param recved the received event, if you don't care, RT_NULL can be set.
 *
 * @return the error code
 */
rt_err_t rt_event_recv(rt_event_t   event,
                       rt_uint32_t  set,
                       rt_uint8_t   option,
                       rt_int32_t   timeout,
                       rt_uint32_t *recved)
{
    struct rt_thread *thread;
    register rt_ubase_t level;
    register rt_base_t status;

    RT_DEBUG_IN_THREAD_CONTEXT;

    /* parameter check */
    RT_ASSERT(event != RT_NULL);
    RT_ASSERT(rt_object_get_type(&event->parent.parent) == RT_Object_Class_Event);

    if (set == 0)
        return -RT_ERROR;

    /* init status */
    status = -RT_ERROR;
    /* get current thread */
    thread = rt_thread_self();
    /* reset thread error */
    thread->error = RT_EOK;

    RT_OBJECT_HOOK_CALL(rt_object_trytake_hook, (&(event->parent.parent)));

    /* disable interrupt */
    level = rt_hw_interrupt_disable();

/* check event set */
if (option & RT_EVENT_FLAG_AND)
{
    if ((event->set & set) == set)
        status = RT_EOK;
}
else if (option & RT_EVENT_FLAG_OR)
{
    if (event->set & set)
        status = RT_EOK;
}
else
{
    /* either RT_EVENT_FLAG_AND or RT_EVENT_FLAG_OR should be set */
    RT_ASSERT(0);
}

if (status == RT_EOK)
{
    /* set received event */
    if (recved)
        *recved = (event->set & set);

    /* received event */
    if (option & RT_EVENT_FLAG_CLEAR)
        event->set &= ~set;
}

else if (timeout == 0)
{
    /* no waiting */
    thread->error = -RT_ETIMEOUT;
}

else
{
    /* fill thread event info */
    thread->event_set  = set;
    thread->event_info = option;

/* put thread to suspended thread list */
rt_ipc_list_suspend(&(event->parent.suspend_thread),
                    thread,
                    event->parent.parent.flag);

/* if there is a waiting timeout, active thread timer */
if (timeout > 0)
{
    /* reset the timeout of thread timer and start it */
    rt_timer_control(&(thread->thread_timer),
                     RT_TIMER_CTRL_SET_TIME,
                     &timeout);
    rt_timer_start(&(thread->thread_timer));
}

/* enable interrupt */
rt_hw_interrupt_enable(level);

/* do a schedule */
rt_schedule();

        if (thread->error != RT_EOK)
        {
            /* return error */
            return thread->error;
        }

        /* received an event, disable interrupt to protect */
        level = rt_hw_interrupt_disable();

        /* set received event */
        if (recved)
            *recved = thread->event_set;
    }

    /* enable interrupt */
    rt_hw_interrupt_enable(level);

    RT_OBJECT_HOOK_CALL(rt_object_take_hook, (&(event->parent.parent)));

    return thread->error;
}
RTM_EXPORT(rt_event_recv);